M101 The Northern Pinwheel Galaxy
Description: M101, the Northern Pinwheel, is located in the constellation of Ursa Major. This image was taken on July 4, 2008 at the Golden State Star Party near Adin in northeastern California. I've attempted to get images of this galaxy before, but the transparency at my home near Seattle, Washington is such that I always have a hard time getting the fainter parts. While the object's magnitude - and presence on Messier's list - would lead you to believe that it's fairly bright, it is very large in the sky with a deceptively low surface brightness. This image turned out pretty well and I am happy with it. It was much better placed in the sky compared to the M20 shot from the same night.
Equipment: The image was taken with an 8" Meade LX200ACF telescope on a Celestron CGE mount. The camera was an SBIG ST10XME with an Astro-Physics .67 Telecompressor and Astrodon filters. The guide scope and camera were an Orion ST-80 refractor with an SBIG remote guide head attached to the ST10. Focusing was done with an Optec TCF-S focuser with temperature compensation turned off.
Exposures: 12x300 seconds luminance binned 1x1; 10x300 seconds each red, green & blue exposures binned 2x2.
Processing: Bias, dark & flat calibration, image registration & color registration were done in Maxim/DL. Curves, levels, LRGB combination, zone sharpening & noise reduction were done in Photoshop CS2. Gradient processing was done with GradientXTerminator.
Click on image for full resolution.